The present invention relates to an apparatus for moistening the closure flap of an envelope during automatic mail handling.
In mail handling machines, moistening devices are used to wet the flap of an envelope in preparation for sealing the envelope. Conventionally, this wetting is done by feeding the envelope past a stripper blade having a moistening brush attached thereto, which allows the wet brush to come into contact with the glue on the envelope flap. The water causes the glue to soften and become tacky to the touch. The envelope is then fed between two sealing rollers which press the flap against the envelope body to form the seal. The envelope is then either ejected into a stacker or passed on to another part of the mail handling machine for further processing.
As shown in U.S. Pat. No. 4,380,210 for a Workpiece Moistening System, issued Apr. 19, 1983 to David Auerbach and assigned to the assignee of the present invention, it is known in the art to manually move a plate over the moistening device to selectively dispense a "dry" or "wet" envelope. Moreover, as shown in U.S. Pat. No. 4,380,209 for a Workpiece Moistening Apparatus, issued Apr. 19, 1983 to Robert R. Reid, et al, and assigned to the assignee of the present invention, it is known in the art to provide moistening structure comprising a brush including a base with a plurality of teeth and bristles extending from the base. The bristles have a free end for contacting and applying moisture to an envelope. A brush holder also includes a plurality of teeth for slidable engagement with the brush teeth.
Typically, the moistening device includes a reservoir for introduction of water or a similar fluid into the moistening apparatus. The fluid level in the reservoir must be maintained above a minimum level to ensure that a suitable amount of moisture is applied to the envelope flap. In some cases, visual observation of the water in the reservoir may be possible if the reservoir tank is transparent or contains a transparent window which allows observation of the water level. In other cases, the reservoir is situated in the moistening apparatus such that observation is not possible. In general, even when the water level is observable, some form of fluid level detection is required to prevent the water level from inadvertently falling below the minimum level.
As shown in U.S. Pat. No. 5,156,048 for an Electronic/Magnetic Apparatus and Method for Detecting Fluid Level, issued Oct. 20, 1992 to Carlos L. DeFigueiredo, et al, and assigned to the assignee of the present invention, it is known in the art to combine the use of one or more Hall effect sensors and a float containing two magnets in push-pull configuration to provide an accurate, low cost system of fluid level detection.
Notwithstanding the aforesaid prior art, there has been a long felt and as yet unsatisfied need to provide an envelope flap moistener wherein the flap moistening apparatus is constructed and arranged for appropriately, but not excessively, wetting the envelope flaps.